Welcome to the M4 web site. This page provides a very brief description of our project. For more information, please follow the links at:http://cfa-www.harvard.edu/~agoodman/m4/m4_99.html.
M4 is a proposed NASA Small Explorer (SMEX) Satellite. M4 stands for "Milky Way Magnetic Field Mapping Mission."
M4 will spend about 3 months mapping polarized thermal emission from dust in the inner Milky Way, selected star-forming regions, and selected high-latitude regions at 100 microns wavelength. From the polarization maps, we will be able to construct a three-dimensional picture of the structure of the magnetic field in the Milky Way Galaxy.